The Bloop...       Last Edit:  August 14, 2015
a motorfloater for recreational Mike Sandlin
  The Bloop 2 is a simple, slow flying biplane with a small motor.






 Bloop 2 Technical Drawings (93 pages).

These drawing downloads are free and may be used for any purpose.

As bitmaps
,in zip folder download:    Blooop 2

Drawings as bitmaps, viewed online in Picasa :'s Gallery 
(The Picassa bitmap drawings will be the first ones updated when changes are made, the Picassa photo captions describe the change, and the date on the drawing will be that of the latest revision. Compare dates of the CAD file drawings to the online versions to see if changes have been made.)

In a CAD (Computer Assisted Design) format, requiring a CAD program or viewer, 
zip folder download: 

(These DXF drawings are not the best CAD for the Bloop because they were produced from Turbocad TCW, they are buggy, the groupings and layerings are imperfect, the text had to be exloded and looks crude. They are okay for viewing but not the best for rework or modification).

In the native CAD format, highest quality, requiring a Turbocad program,
zip folder download:

Bloop 1
Technical Drawings (92 pages).
These are drawings of the the previous version of the Bloop, the Bloop 1 (twin rudders),
not the the current version, the
Bloop 2 (single rudder). See the Photo Gallery for Bloop 1 photos.
As bitmaps
,  zip folder download: Bloop 1

      Drawings as bitmaps, viewed online in Picasa :'s Gallery
      (The Picassa bitmap drawings will be the first ones updated when changes are made, the Picassa photo captions describe the change, and the date on the
      drawing will be that of the latest revision. Compare dates of the CAD file drawings to the online versions to see if changes have been made.)

In a CAD (Computer Assisted Design) format, requiring a CAD program or viewer, zip folder download:
(These DXF drawings are not the best CAD for the Bloop because they were produced from Turbocad TCW, they are buggy, the groupings and layerings are imperfect, okay for viewing but not the best for rework or modification)

In the native CAD format, requiring a Turbocad program,
zip folder download:


What is the idea ..?

A motorfloater is an ultralight airplane with a small motor that flies very slow. The pilot sits completely out in the open, flying in a simple and easy way. Flying a motorfloater is a lot like flying a paramotor but with the stability, control, wind tolerance, and crash safety of a light airplane or airchair. Exposed flight is comfortable at low speeds, allows an excellent view, and provides a special kind of flight experience.

The motorfloater differs from other airplanes in having a very light wing loading, allowing slow flight and tight turns.
A motorfloater wing loading is similar to that of a hang glider (less than 2 pounds of gross weight per square foot of wing), and it has a light empty weight  (United States FAR Part 103 compliant, less than 254 lbs.). My idea of a motorfloater differs from paramotors, powered hang gliders, and microtrikes in having a tail (for pitch stability), a fixed rigid wing (again for stability, without fabric canopy issues), and more fixed structure around the pilot (for crash protection). A motorfloater does not try to be everything that heavier airplanes are, it is more of a motor scooter with wings.

Motorfloaters can be made strong  and durable and still stay within the FAR Part 103 weight limits, as long as we are willing to fly without the extraneous weight that comes from doors and windows, big engines and big fuel tanks, heavy tires, brakes and ground steering, electrical systems, extensive instrumentation, and the streamlining associated with high speed flight. All of that heavy stuff is really more of a burden than a benefit, anyway, if your goal is simply to fly for fun once or twice a week. (I would also like to say that we can dispense with the extra weight of the rocket deployed emergency parachute (by using a hand deployed system) and dispense with the ailerons, as I do, but  this is more controversial).

I designed and built the Bloops1 through3, motorfloaters which have been flying since July, 2011, and have proven to be enjoyable recreational airplanes. The Bloop 3 measured level flight cruise speed is 25 miles per hour, flying in the speed range of the hang gliders and paramotors. It is perhaps the slowest motorized airplane ever, fulfilling its design goals.

I use simple controls, garage technology construction, and a paramotor engine. The stall and spin characteristics (if any) should be very mild and forgiving, and an unaccelerated stall with moderate weight pilots does not have any abrupt results. At my weight I can fly with the control stick full back and still maneuver, although the nose nods up and down, and the sink rate is high. The emergency parachute is hand deployed, as it might be on a hang glider or a trike, a realistic option when the pilot is out in the open.

The Bloop is built mainly of aluminum tubes bolted together and braced with braided steel cable, covered overall with light but conventional aircraft fabric. This "garage construction" involves using mostly a hand held power drill and a hacksaw, not using any welding, sheet metal, specially machined parts, jigs, molds, nor a spray rig.

The Bloop was originially the Pig glider, with an engine added later. (See the Pig Page for details on this airchair glider.)  The Bloop 3 with engine and emergency parachute weighs about 204 pounds. The power package is a
modern paramotor system, a Vittorazi Moster 185 two stroke engine (25 hp.) with a 1.3 meter two bladed propeller (same for Bloop 1 and Bloop 2). The engine is started by a rope pull (recoil) and uses synthetic oil mixed into the Avgas fuel. In flight I use two instruments: a tachometer (engine crankshaft speed in revolutions per minute) and an exhaust gas temperature gage.

For simplicity,
the Bloop has no ailerons, the plane is controlled by the rudder (or rudders) and elevator only. This is a traditional two axis system (ala Weedhopper, Flying Flea, Skypup, early Quicksilver MX, etc.) which requires two axis flying procedures. For example, when you are rolling on the ground in a cross wind, you keep the nose low so the weight is on the wheels, which will keep the wings level. Taking off or landing in a crosswind requires maintaining a crab angle rather than a slip when the wheels are not on the ground. Ordinary flight maneuvers are accomplished with the two axis system in essentially the same way as the three axis system, such that an experienced pilot may soon become indifferent as to which system is in use.
I don't taxi much, I walk the plane to and from the runway, which is practical with a well balanced airplane that isn't heavy. A pilot who walks his plane instead of taxing can see better, has better control, and is safely out of the plane if extreme weather suddenly arrives. Walking the plane reserves your hot engine time for flying instead of ground travel, and it avoids raising dust and making noise at the airport.
In consideration of other air and runway traffic, the Bloop can scoot onto or off the runway with the pilot seated when necessary.

It is often asked why the Bloop does not use a more conventional landing gear system, with a tail wheel or nose wheel. My answer is that I have not seen a conventional nose wheel or tail wheel setup that would allow for high wind safety at this low wing loading.
A motorfloater must be able to roll with the nose low and stop with the nose down, firmly gripping the ground, so it will not be blown away. The wheels of the Bloop are located near the center of lift, so the pilot can choose stop on the tail skid or the nose skid. The start and stop positions in substantial wind are expected to be nose down on the skid, like a sailplane trainer or an airchair glider.

The Bloop is a "put-put" for local flights, just for fun. This is a non-commercial project, so nothing is for sale, but I encourage commercial production of a motorfloater like this. All of the materials on my websites are freely available for whatever purposes the user may desire.

Comments After Four Years of Bloop Flying:

Light Wing Loading:
The light wing loading of the Bloops has proven to be a benefit for reasons of easy and comfortable flight. Ordinary winds, especially early or late in the day, have not proven to be restrictively turbulent, or even bothersome.

Part 103 Ultralight: It has been a liberating experience to operate as an ultralight, to build and modify aircraft equipment and procedures without formal oversight. The Bloop 3 has a 74 lb. margin under the weight limit (with parachute allowance), the fuel tank uses only half the 5 gallon allowance, and the airspeed limits are easily met.

Two Axis Control: The Bloop has shown that some of the traditionally recognized shortcomings of the rudder/elevator control system can be corrected by design. The Bloop is designed for a nose down ground roll attitude, which puts the aircraft weight on the widely spaced wheels, keeping the wings level while ground rolling in cross winds. This ability, and the slow airspeeds, have pretty much eliminated the cross wind condition as any kind of serious problem for two axis motorfloaters. I'm doing the same recreational flights with two axis control that I would have done with three, the differences are trivial.

Paramotor Engine: The thrust of the small engine is quite adequate for satisfying flight, and the low rate of fuel consumption is gratifying and makes for a low burden of fuel handling.

No Taxi: Lifting the plane by the tail and rolling it like a sailplane, to or from the flight line, instead of taxiing, has been practical and convenient. An ultralight does not need to be moved with a motor.

Hand Deployed Emergency Parachute: No serious issues have developed with the outdoor version of the total recovery system, it is light, easy to inspect, and out of the way, as it would be on any paraglider or hang glider. It has not been deployed, but I sometimes pull it out of the bag while seated at the tie down as a functional check.

Flight Instruments: Engine temperature and engine speed gages are my only flight instruments, they are needed on the ground for diagnostics but I can't think of any time when they were important in the air. The airspeed reference is nose attitude and wind feel, which is inexact, but being fast or slow is not much of a hazard in the Bloop.

Garage Technology: How can I go wrong with simple parts attached simply, using simple tools? Experiments, upgrades, repairs and replacements were easy and fast.

Free Standing Center Section: Having a built up center section was a great benefit to Bloop 3 construction, I could attach new parts to it and set everything up without having to assemble the whole airframe in the backyard.

Bicycle Wheels and Skids: Fat BMX bicycle wheels are good for the dirt, easily replaced or repaired locally, and resistant to leaks from thorns when charged with slime. Stiff on landing impact (lacking other elastic suspension), but good enough. The skids are practical but wear out fast on paved runways. Using the nose skid as a ground brake has been simple and adequate.
Outside Tie Down: Always being exposed accelerates corrosion, which is not good for the plane in any way, but with the use of cockpit and engine covers, I find it acceptable. With a thorough silvering job the wing fabric can endure the sun exposure. I don't have to maintain a hangar, and can make a quick start.

Unpaved Runways: Flying off dirt feels soft, stable and more forgiving, compared to pavement.
Aircraft Radio: I use a headset radio because it is required at my airport, but I would need ear protection anyway because of the engine noise. To transmit, I usually throttle back to idle to reduce the engine noise, and even then I don't know if I am being heard. Often I do not hear others. I follow the rules but don't consider my radio to be any substantial contribution to safety, it's more of a distraction, I'd rather not fly with it.

Various Airfoils: I've flown with three different airfoils, they all fly about the same, wing loading seems to be the important factor.

Aircraft Balance: Bloop 2 had the pilot way forward with 5 degrees of horizontal tail crank holding the tail down, whereas Bloop 3 has the pilot farther back and 3 degrees of tail crank holding the tail down. These setups fly a little differently and each has its advantages.

Open Air Flight: I like this, I feel like I am out there and really flying when I see and feel all. Low speed flying is comfortable, I often fly in a tee shirt and hiking shorts.

Paramotor Pilot Conversion: The Bloop seems to me to fly a like a paramotor without canopy issues, perhaps a motorfloater that paramotor pilots can fly with familiarity.

For developments see the Bloop News page.


The pilot decides whether to stop on the nose skid or the tail skid.

An unobstructed view with good ventilation

Without ailerons, only the rudder pedals are used for turning.